Comparative risk of Guillain–Barré syndrome recombinant and live zoster vaccines: a pharmacovigilance study using VAERS and EudraVigilance database

This study aimed to compare the risk signals of Guillain-Barré syndrome (GBS) associated with recombinant zoster vaccine (RZV) and zoster vaccine live (ZVL) to improve understanding of herpes zoster vaccine safety. Disproportionality analyses were conducted using the Vaccine Adverse Event Reporting System (VAERS) and validated using the EudraVigilance database. Reporting odds ratio (ROR), proportional reporting ratio (PRR), and information component (IC) methods were applied, followed by time-to-onset and logistic regression analyses. A total of 482 GBS reports associated with RZV and 85 reports associated with ZVL were identified in VAERS. Significant disproportionality signals were detected for RZV but not for ZVL. Most GBS cases occurred within 30 days after RZV vaccination. Time-to-onset analysis indicated an early-failure pattern. Multivariable analysis showed that male sex and age ≥65 years were associated with an increased reporting risk of GBS following RZV vaccination. Sensitivity analyses restricted to cases occurring within 42 days of vaccination and to vaccines administered alone yielded consistent findings. Similar disproportionality signals for RZV were observed in EudraVigilance. This pharmacovigilance study identified a disproportionate reporting signal of GBS associated with RZV but not with ZVL. Although causality cannot be established, continued post-marketing surveillance of neurological adverse events following herpes zoster vaccination is warranted.